Blind spot detection: Car tech that watches where you can’t

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Early on in Drivers’ Ed, you were taught to look over your shoulder before changing lanes because side view mirrors don’t see everything. What you may miss in a quick glance is what blind spot detection picks up. This driver assistance technology senses cars coming up in your blind spot behind or alongside you, and if your turn signal is on, it alerts you not to change lanes. You’re warned by a flashing light on the side view mirror and then a beep or steering wheel vibration. If you’re not planning to change lanes (there is no turn signal on), the warning light glows steadily but doesn’t flash and there’s no audible alert.

Blind spot detection is a key technology among driver aids that provide 360 degrees of electronic coverage around your car, whether you are at speed or moving slowly. This circle of safety also includes adaptive cruise control, lane departure warning, rear and front parking sonar, the rear traffic alert, and parking cameras (ranging from rear-only through four cameras providing a birds-eye view of the car as you snake into and out of tight spaces). Some driver’s aids make you safer, especially late on a long drive, and some earn back their cost when you don’t crumple a fender, where the insurance deductible costs more than the device.

Blind spot detection vs. lane departure warning vs. parking sonar

Three technologies protect the side and back of your car: blind spot detection, lane departure warning, and rear parking sonar. Here’s how they differ:

Blind spot detection (BSD) was developed by Volvo a decade ago. BSD tracks traffic just behind you as well as what’s coming alongside. The alert stays active until the car in the adjacent lane is in front of you, or at least directly alongside and you’d have to be blind not to see it. It doesn’t care if you are in your lane or have drifted a bit into the next and are at risk of sideswiping another car. BSD uses ultrasonic or radar sensors on the side and rear of the car.

The name comes from the blind spot to the side just behind the car where you may not see a car because the mirror doesn’t cover and if you turn your heard, it could be obscured by the B-pillar (the one between the front and back seat on four-door cars). The visual alert is a yellow (usually) indicator in the side mirror glass, inside edge of the mirror housing, or on the A pillar inside the car. It lights when it senses a car in the blind spot and flashes if the turn signal is flashing. You’ll also get an audible alert (beeping) or an induced vibration or light shake of the steering wheel if the turn signal is flashing.

The system is called blind spot detection, blind spot monitoring, and blind spot information system, depending on the maker, but it’s all the same thing. The first two are almost equal in frequency of use. BLIS is used by Ford, Lincoln and Volvo. Audi calls it Side Assist, General Motors side blind zone alert, and Infiniti’s name is blind spot warning. You’ll also see active blind spot monitoring.

The opposite, passive blind spot monitoring, means — wait for it — looking in the side mirror. Just as the names vary, so does the performance. Some only detect cars once they’ve overlapped your rear bumper (that is, already alongside), while others detect cars 3-5 car lengths back.

Blind spot detection also works (as BSD) to spot cars and trucks; even motorcycles and bicycles have enough mass to be sensed. Although: How often are you overtaken by a bicycle?

Lane departure warning (see our tech LDW backgrounder) tracks whether you’re centered in your lane or not. It uses a forward-facing camera usually in the rear view mirror mount so it’s typically an optical system. If you drift across the lane, you get a visual alert in the dashboard and an audible alert or a steering wheel or seat bottom vibration. If your turn signal is on, you won’t get an alert; the car assumes you intend to cross over lanes. That’s the opposite of BSD, which gives a full alert with the turn signal blinking, because the car fears you’re about to move into the path of another car.

Parking sonar uses ultrasonic (usually) or electromagnetic sensors in the back and sometimes front of the car to judge how close you are to objects nearby. Sometimes the sensors are part of the blind spot detection and cross traffic alert (see below) systems. They work like sonar in a U-boat movie: the sensor sounds a ping when it first senses an obstacle and the pings get more frequent, becoming a solid tone at about a foot away. You can have parking sonar (also park distance control, park assist, or Parktronic) without blind spot detection.

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Torqueobama

Excellent article, though you did leave out the BSAC alternate. (Blind Spot Aversion Conditioning – a low intensity microwave beam to make it uncomfortable to hang out in someone’s blind spot for any length of time).

Ian Skinner

.. how about we stop making gadgets that facilitate lazy drivers and train drivers from the start to BE better..

Bill Norton

There is so many things wrong with this statement, I don’t even know where to start.

Ian Skinner

Apparently not wrong enough for you to type, so it can’t be that horrible. Regardless, my statement is echoed closely by many performance driving instructors, north america has some of the lowest standards of driver training in the G20. These gimmic items do nothing to improve that , only mask shortcomings.

Ray C

I agree that for the most part you really don’t have to learn that much about how to drive before getting your license in the U.S. There isn’t really even much in the license test manual. IF you can remember a few signs and a couple of rules and you can make it around the block, you have a license. I think this device will help some. But I also find that I can avoid a collision just as well by adding blind spot mirrors, use the proper technique for checking mirrors, or doing a quick look over my shoulders. I’m not sure I would call everyone lazy drivers, but I do think technologies give people a false sense of security and make them not follow procedures they usually would.

Techutante

Yes and now, however you have to realize most of the features are still reserved for high-end much newer cars that new drivers ought to be driving. They should get a shitty junker car like the rest of us started with, so they can hit a few things with it and learn to drive properly.

Cohort Seven

When I’m watching a video and texting, I want the warning to come up right on my Iphone. It’s a drag to look out the window at all and I do it as little as possible.

Matt Hoshiko

These advances in technology are not solely for lazy drivers, but it helps those such as myself who have some visual deficits due to a brain injury and allows them to continue to drive safely and remain capable of everyday life without having to rely on other people to drive them on a whim.

Ian Skinner

ok, I can see this being a good use of tech, but you don’t want everyone to have wheel chair access parking lic plates when it should be reserved for those that truly need it.

Matt Hoshiko

These advances in technology are not solely for lazy drivers, but it helps those such as myself who have some visual deficits due to a brain injury and allows them to continue to drive safely and remain capable of everyday life without having to rely on other people to drive them on a whim.

Jacob Wadsworth

These are very useful devices which can help prevent dents and accidents which may lead to unnecessary expenses. The thing with these devices though is that drivers tend to rely on them too much that when they malfunction, may lead to grave circumstances. – http://www.gripdaddymounts.com/

Monty

If you are looking for an alternative to the little stick on convex blind spot mirrors, have a look at Maxi View Blind Spot Mirrors. They have both a towing mirror & regular mirror. The towing mirror is recommended for vehicles over 30 feet long, combos over 40 feet long from mirror to rear bumper, or over 7 1/2 feet wide. Mirror lenses are chromed with 4 layers of much thicker metal and passed a 2 year simulated salt and weather test. Full focus for every driver of any height; fully adjustable, 360° ball and socket swivel, guarantees every size driver will see the blind spot, two car lengths long and two lanes wide. See for yourself at http://www.MaxiViewMirror.com.

Ray C

I’ll check it out, but my stick on mirrors work just fine for me

sparkeyjames

Turn your head while not turning the car. Yes it really is that simple.

Cohort Seven

It scares me to look at all those cars around me. I want a computer on my car to do it for me. Besides, I’d rather look at videos as I drive.

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